Many kinds of beverage flavoring agents or drink mixes are commercially available in powdered or granulated form. Such agents/mixes are easily transported, stored, and sold separately from a solvent fluid such as water. This is economical for the manufacturers, distributors, retailers, and consumers in that the steps of having to measure and mix the drink mix with water, packaging the pre-mixed beverage in a fluid-tight container, shipping the pre-mixed beverage, and possibly storing the pre-mixed beverage in a refrigerated case are eliminated prior to purchasing by the consumer. There is, however, a penalty of inconvenience in that the consumer must provide a suitable container when the mixing of ingredients is to take place.
A proposed solution to this problem has been to provide a closure for the container which contains a pre-measured amount of the drink mix. U.S. Pat. No. 3,743,520 (Croner) discloses a metal beverage can having a plurality of drink mix compartments formed on the underside of a substantially flat container lid. A can opener is needed to pierce the lid and one or more of the compartments, thereby allowing the drink mix to fall into the container. To keep the top wall of his container flat to allow for stackability, Croner's closure is unnecessarily complicated, requiring two sheets of metal bonded or welded together to form the top flat wall of the closure and crimped to a third sheet of metal having the storage compartments formed therein. This is not only complicated to manufacture, but may be difficult for some persons to open with a can opener.
U.S. Pat. No. 3,548,562 (Schwartzman) discloses a screw-on closure having flexible side walls and a seal defining a single large dome-like storage compartment for holding a liquid. Two puncture rods are formed on an interior wall of the storage compartment, operable by pressure on the top walls of the closure to puncture the seal and allow the liquid to fall into the container. The Schwartzman closure is not only bulky and nearly impossible to stack, but, due to the unprotected flexible side walls which define both storage compartment and lid, is easily ruptured by accident.
U.S. Pat. No. 4,264,007 (Hunt) discloses a container having a pull-off or peel-off tab on the closure which, when removed, causes a cup-shaped drink mix compartment formed on the underside of the closure to pivot and dump its contents into the container. This structure is complicated and impractical, requiring two layers of lid material, a pull-tab, means for connecting said pull-tab to the storage compartment through the lid surface, and pivoting means for the storage compartment.